The prior art discloses that the preparation of chlorofluorocarbons, hydrofluorocarbons and hydrochlorofluorocarbons is typically carried out by reacting hydrogen fluoride with a suitable chlorocarbon or hydrochlorocarbon. See, for example U.S. Pat. No. 5,616,819.
In many cases, hydrogen fluoride can be removed by liquid/liquid phase separation. Such phase separation is readily achieved because of the relative immiscibility of the hydrofluorocarbon (or chlorofluorocarbon or hydrochlorofluorocarbon) and hydrogen fluoride.
Contrary to the ready immiscibility of the older prior art halocarbons with hydrogen fluoride, some of the new "third generation" hydrofluorocarbons have proven to be highly or completely miscible with hydrogen fluoride, i.e., 1,1,1,3,3-pentafluoropropane) and practical phase separation does not occur.
It has been recognized that the selective extraction of one component of a mixture of halocarbon and hydrogen fluoride may be carried out using a solvent capable of such selective extraction. However, the new "third generation" hydrofluorocarbons have been found to be partly or completely miscible with such solvent/hydrogen fluoride mixtures making such selective extraction very difficult or impossible.
Numerous normally effective separations additives, i.e., 4-chlorotoluene, pentachloropropane, tetramethylamine fluoride, etc. have been shown to be completely ineffective in causing any phase separation in saturated fluorinated aliphatic hydrocarbon/hydrogen fluoride systems.
In the aforementioned U.S. Pat. No. 5,616,819 sodium fluoride, potassium fluoride and ammonium fluoride are disclosed as effective in causing phase separation when added to fluorocarbon/hydrogen fluoride mixtures. Each is, however susceptible to technical problems in large scale applications
Accordingly, there is a need for having available methods and compositions to carry out such methods to achieve phase separation of hydrofluorocarbon/hydrogen fluoride mixtures.